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F. PEARCE & J. JONES.

- LOOK FOR FIRE ALARM BOXES.

1109280506. Patented July 3, 1883.

UNITED STATES PATENT Gr nch.

FREDERICK PEARCE, OF NEWV YORK, AND JAMES JONES, OF BROOKLYN, N. Y.

LOCK FOR FIRE-ALARM BOXES.

SPECIFICATION forming part of Letters Patent No. 280,506, dated July 3,1888.

Application filed April 14. 1883; (Model) T0 at whom it may concern Beit known that we, FREDERICK PEARCE and JAMES J oNEs, citizens of theUnited States, residing, respectively, at New York, in the countyof NewYork, and Brooklyn, in the county of Kings, and State of New York, haveinvented certain new and useful Improvements in Locks for Fire-AlarmBoxes; and we do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, and to the letters and figures ofreference marked thereon, which form a part of this specification.

This invention relates to a key -trapping mechanism for use inconnection with firealarm boxes and in other situations in which themisuse of a key is suspected.

The invention consists in the combination, with a lock, of a trappingmechanism embodying a pivoted plate, one end of which is adapted topartially cover the k ey-h ole of the lock and prevent the removal ofthe key after the door has been unlocked and opened; and, further, incertain details of construction, as hereinafter more fully described andclaimed.

In the annexed drawings, illustrating our invention, Figure l is aninterior view of the lock with the principal key-hole covered, the partsbeing in the position into which they are moved by the act of openingthe door and the hinged lid of the case.

trapping the key. Fig. 2 is a similar view, showing the trappingmechanism set for action. Fig. 3 is a vertical edge view of the lock.Fig. 4 is a view of the case in which the trapping mechanism isinclosed. Fig. 5 is also a view of the case inclosing the trappingmechanisnuthe hinged lid of the case being raised, so as to expose a pinor pins by which the trapping device is moved away from the principalkey-hole, thereby uncovering the same and setting the mechanism forfurther use. Fig. 6 is a view of the under side of the case in which thetrapping mechanism is inclosed, and shows a spring-catch for securingFig. 7 is a detail.

Like letters designate like parts in the several views.

A represents a spring-lock of any ordinary or suitable construction, andB is a casing arranged beneath the casing of the lock A, andcommunicating therewith. In the casing B is arranged a trappingmechanism for catching a key inserted into the key-hole of the lock A toopen the door to which said lock is attached.

The trapping mechanism consists, essentially, of a pivoted plate, 0,that is adapted to be moved by the act of opening the door, so as topartially cover thekeyw-hol e of the lock A and prevent the key beingturned sufficiently to be removed or disengaged from thelock. Thepivoted trapping-plate O is provided with a pin, a, that projectsthrough a slot, 1), in the case B, as shown in Fig. 5. It also has alug,c, for engagement with alug, d, on a flat spring, D, by which thetrappingplate is held away from the keyhole. The lower corner of thetrappingplate nearest the jamb or casing of the door is provided with awedgeshaped projection or lug, e, that is adapted to pass through anopening, f, in the side of the easing B, and by hearing on the inneredge of the door-jamb prevents the pressure of the same against thespring D from springing or releasing the trapping-plate C until the dooris opened. To the rear side or edge of the trapping-plate0 is attached aspring, E, that bears against the lower end of said plate and forces itsupper end over the keyhole, thereby trapping the key. The forward sideor edge of the plate G is notched at g for engagement with a hooked dog,F, Figs. 1 and 2, that is actuated by a spring, h, and carries a pin, i,which projects through a slot, 70, in the casing B, as shown in Fig. 5,a stop-pin, m, Figs. 1 and 2, being arranged to prevent the dog F beingforced out of position byits spring.

The case B, inclosing the trapping mechanism, is provided with slots band for passage of the pins a t, as before mentioned. These pins areordinarily concealed by a hinged lid, G, that covers the entire surfaceof the case, the under side of said lid being provided with a notchedlug, 1), that passes through an opening, s, inthe case B, and is held bya springcatch, H, on the under side of the case. The hinged lid G isprovided with an opening, 2, for the passage of a key into and through akey-hole, w, in the case B, by which the catch H may be disengaged fromthe lug p, thereby permitting the lid to be raised to give access to thepins by which the trapping-plate (,1 is witlnlrawn from. the principalkey-hole.

The operation of the device is as follows: By inserting a key throughtheopening 1 and key-hole w the lid G may be unlocked and raised, thusexposing the pins a and i, which may then be forced back, so as to movethe upper end of the plate C away from the keyhole of the look A, whereit is held by the lug 0, bearing against the lug (Z on the spring I).The door K, to which the lock is attached, may now be closed, thespring-actuated bolt of the look A securing the door until it isnecessary to be opened. The act of closing the door brings the end ofthe spring D in contact with a ledge or projection on the inner edge ofthe door-jamb and forces the spring back against the door, therebydisengaging the lugs c and d, permitting the lug e to drop into abeveled indentation in front of the lug d, and permitting the plate 0 tomove sufficiently to luring its lug 0 against the inner edge of thedoorjamb, in which position the trapping mechanism remains set until thedoor is opened. \Vhen it is desired to unlock and open the door, a keyis inserted into the key-h ole ot' the look A to draw its bolt, and theact of opening the door by releasing the lug e from its pressure on theinner edge of the door-jamb enables the spring E to force the lower endof the trappingplate (l forward, thus causing the upper end of the saidplate to move backward and cover the lower portion of the key-hole, soas to prevent the removal of the key. l'n order to remove the key, thehingedlid G of the case B will be unlocked, as before described, and thepin (I moved back to partially rotate the plate Uand uncover theprincipal keyhole, so that its key may be disengaged. \Vith theconstruction shown, before moving the pin (I it will benecessary to movethe pin 1' to disengage the deg F from the notch g of thetrapping-plate;but, il'desired, the deg F may be dispensed with.

It will be seen that by this mechanism akey used to draw the bolt of thelook A will be invariably trapped or detained in the look, its removalbeing impossible without previously unlocking the case 13 and settingthe trapping mechanism back. thus be readily detected.

The device is applicable for use in connec tion with fire-alarm boxes,or in other situations where the misuse of a key is to be detected.

lit will be observed that the hinged lid G, when closed, conceals thescrews by which the casing B is secured to the door K, so that after thedoor has been opened and the principal key trapped it will beimpossibleto reach the screws for the purpose of removing the casing 13without the possession of the auxiliary key for unlocking the lid orcover G of said casing.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is

1. The combination, with the lock A, of the casing B, having slots a k,the pivoted trap ping-plate 0, having notch g, pin a, and lugs c c, thespring-dog F, having pin '6, the spring E, and the spring D, providedwith lug (1, substantially as shown and described.

2. The combination, with the look A, the door K, and its casing, of theslotted case B, having a lid, G, adapted to conceal, when closed, thescrews by which the case B'is secured to the door, the pivotedtrapping-plate 0, arranged to project into the case A, and to obstru ctthe key-passage in said case, and having pin a. and lugs c c, the springE, and the spring I), having lug (I, substantially as shown anddescribed.

In testimony whereof we altix our signatures in presence of twowitnesses.

FREDK. PEARCE. JAMES JONES;

\Vitnesses:

ANDREW 13 LA KE, (mom: n H. T MLvN.

The misuse of a key can

